1. Field of the Invention
The present invention relates to an image processing apparatus that processes observation images in which a cell is recorded, and a computer program product thereof.
2. Description of the Related Art
In a cell, genetic information doubles because of DNA replication, and doubled genetic information is allocated to two daughter cells by cell division, which achieves continuous growth white maintaining certain genetic information. When appropriate conditions for growth (growth factor), including rich nutrition, is satisfied, the cell cycle progresses, and if the DNA is damaged due to application of a radiation ray or an ultraviolet ray (DNA damages), the progress stops. The progress of the cell cycle is usually strictly controlled based on factors of, for example, whether DAN damage occurs and whether there is a growth factor. It is considered that the normal control is essential for life. It is said that failure in the cell cycle out of the normal control deeply relates to the process of canceration.
With recently increasing importance of study on the cell cycle, study on the cell cycle, control mechanism, and preventing method has been progressed to find out the mechanism of cancer and develop medical drugs.
Particularly, to find out the cancer mechanism and specify targets of drug discovery, understanding the cell state in the cell cycle is important. Particularly, understanding the phenomenon that a cell divides and grows is important, and there is a demand for accurately detecting cell division. To detect cell division, various kinds of methods have been developed.
Japanese Patent Application Laid-open No. 7-75554 discloses a method of evaluating the growth state using an image in which cells are recorded (hereinafter, referred to as “cell image”). In this method, the size of each cell is obtained by image processing, and the average of the obtained sizes is used as an index representing the level of growth, which makes it possible to statistically evaluate the cell growth state.
Published Japanese Translation No. 2001-5007444 of the PCT International Publication discloses a method of evaluating the state of cell division using cell images. In the image processing in the method, whether it is a cell is determined by comparing the amount of cell characteristics, particularly, the shape characteristics including the area and circumference, with that of a model previously prepared based on the shape characteristics, and the number of cells is obtained. Because the number of cells increases by cell division, cell division can be detected by monitoring the number of cells. Alternatively, by comparing the tendency in the shape characteristics and position with known tendency, division can be detected.
In the method disclosed in US Patent Application Publication No. 2004/0128077 Specification, cell division is detected by calculating parameters of a cell by image processing and chronologically obtaining the parameters of the cell.